topocnt

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;

const bool typetest = 0;
const int N = 3e3 + 5;
const ll mod = 1e9 + 7;
int n;
vector<int> adj[N];
int a[N], b[N], cnt[N];
ll dp[N][N], ans[N][N], gt[N], rgt[N];

void Read()
{
    cin >> n;
    for (int i = 1; i < n; ++i)
    {
        cin >> a[i] >> b[i];
        adj[a[i]].push_back(i);
        adj[b[i]].push_back(i);
    }
}

ll Pow(ll a, ll b)
{
    ll ans(1);
    for (; b > 0; b >>= 1)
    {
        if (b & 1)
            ans = ans * a % mod;
        a = a * a % mod;
    }
    return ans;
}

ll C(int k, int n)
{
    if (k > n)
        return 0;
    return gt[n] * rgt[k] % mod * rgt[n - k] % mod;
}

void dfs(int v, int p)
{
    dp[v][1] = 1;
    cnt[v] = 1;
    for (auto j : adj[v])
    {
        int i = a[j] ^ b[j] ^ v;
        if (i != p)
        {
            dfs(i, v);
            cnt[v] += cnt[i];
            for (int y = cnt[v]; y; --y)
            {
                dp[v][y] = dp[v][y] * C(cnt[i], cnt[v] - y) % mod * (v == a[j] ? ans[i][cnt[i]] : 0) % mod;
                for (int x = max(1, cnt[i] - (cnt[v] - y)); x < y && x <= cnt[i]; ++x)
                    (dp[v][y] += dp[v][y - x] * C(x, y - 1) % mod * C(cnt[i] - x, cnt[v] - y) % mod * (v == a[j] ? (ans[i][cnt[i]] - ans[i][x]) : ans[i][x]) % mod) %= mod;
            }
        }
    }
    for (int i = 1; i <= cnt[v]; ++i)
        ans[v][i] = (ans[v][i - 1] + dp[v][i]) % mod;
    //cout << v << ": " << cnt[v] << " " << ans[v][cnt[v]] << "\n";
}

void Solve()
{
    gt[0] = rgt[0] = 1;
    for (int i = 1; i <= n; ++i)
    {
        gt[i] = gt[i - 1] * i % mod;
        rgt[i] = Pow(gt[i], mod - 2);
    }
    dfs(1, 1);
    cout << (ans[1][n] + mod) % mod;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t(1);
    if (typetest)
        cin >> t;
    for (int _ = 1; _ <= t; ++_)
    {
        Read();
        Solve();
    }
}